1. Field of the Invention
This invention relates to an aerobic composition capable of beginning to polymerize upon contact with oxygen and more particularly it relates to a film-forming composition.
2. Description of the Prior Art
Vinyl compounds are generally easy to handle and are easily converted to crosslinked polymers by the processes of photopolymerization, radiation-induced polymerization and the like. Hence, such vinyl compounds are utilized as fiber treating materials and coating materials for the decoration and protection of various materials such as metals, wood, stone, asbestos, and the like. However, the rate of the polymerization reaction is generally extremely low in these processes when oxygen is present in the polymerization system, due to the polymerization inhibition effect of oxygen. Consequently, it is very difficult to harden the vinyl monomers with crosslinking in air. Therefore, when these vinyl monomers are to be utilized as a coating material, a special apparatus for forming an inert gas atmosphere and large amounts of the inert gas are required for crosslinking and polymerizing the vinyl monomers to produce a protective film.
The apparatus and the inert gas are very expensive and industrial application of this method is difficult. Moreover, when the substrates to be coated are large articles such as bridges, ships, and the like, formation of coating films using these processes is practically impossible.
The present inventors have previously discovered that when water soluble or water dispersible vinyl monomers are polymerized in an aqueous medium, inhibition of polymerization due to oxygen in the air becomes less conspicuous. Moreover, an effective polymerization reaction can be performed using a polymerization initiator which comprises a mixture of at least one tetravalent cerium compound and a chelate-forming compound, or at least one chelated compound of tetravalent cerium, and at least one sulfur compound which produces ions represented by S.sub.x O.sub.y.sup..dbd. (wherein x and y are integers, such that 1 .ltoreq. x .ltoreq. 6 and 1 .ltoreq. y .ltoreq. 7) in the presence of water. (See U.S. patent application Ser. No. 591,860, filed on June 30, 1975.)
However, according to this method, the polymerization or crosslinking reaction begins as soon as the vinyl monomers and the initiator are mixed. Therefore, the mixture cannot be stored as a one-pack type polymerizable composition, but rather, separate components must be mixed just before use. Because of this disadvantage, the development of applications in this field has been limited.